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United States Patent | 5,068,078 |
Hill ,   et al. | November 26, 1991 |
A method for enhancing the uniformity of wall thickness of an article having a high aspect ratio horizontal cross section and produced from a parison in a blow molding process whereby a barrier layer is applied to a selected area of the outer surface of each parison prior to its introduction into the blow molding apparatus, the barrier layer being effective to prevent premature freezing of the blown parison upon contact with a wall of the blow molding apparatus. The barrier layer application apparatus includes a generally contoured pad coupled to a supply of the barrier material, the pad being situated to contact a selected portion of each parison prior to its introduction into the blow molding apparatus.
Inventors: | Hill; Gary (Kansas City, MO); Schoch; Walter K. (Peachtree City, GA); Warkentien; Michael (Independence, MO) |
Assignee: | Sewell Plastics, Inc. (Atlanta, GA) |
Appl. No.: | 535702 |
Filed: | June 11, 1990 |
Current U.S. Class: | 264/512; 264/130; 264/134; 264/513; 425/90; 425/93; 425/522; 425/DIG.115; 427/256; 427/429 |
Intern'l Class: | B29C 049/00; B29C 049/20 |
Field of Search: | 264/516,129,130,134,523,512,513 427/256,393.5,428,429,430.1 425/90,93,522,DIG. 115 |
1662086 | Mar., 1928 | Stuhr | 118/260. |
4478889 | Oct., 1984 | Maruhashi et al. | 427/393. |
4499045 | Feb., 1985 | Obsomer | 264/535. |
4525377 | Jun., 1985 | Nickel et al. | 427/430. |
4534995 | Aug., 1985 | Pocock et al. | 427/430. |
4543277 | Sep., 1985 | Giles | 427/430. |
4550008 | Oct., 1985 | Shimizo | 264/130. |
Foreign Patent Documents | |||
227624 | Aug., 1984 | DD. | |
966009 | Aug., 1964 | GB | 427/428. |